Additive manufacturing involves adding materials together, layer upon layer, until a three dimensional object is completed. There are a variety of different types of additive manufacturing involving systems that selectively deposit material to build the desired object and systems that selectively solidify parts of a layer of a build material to build up the desired object.
Three dimensional printing includes relatively new forms of additive manufacturing that incorporate the advantages of digital processing. In three dimensional inkjet printing, liquid binder is injected into successive layers of powder to form successive cross sections of the three dimensional object, one layer at a time. Each layer is created on top of the preceding layer until the object is completed.
In another three dimensional printing approach, digital light processing involves hardening a liquid polymer layer positioned between a base plate immersed in the liquid and digitally controlled lights. The liquid superjacent the base plate is exposed to a digitally controlled pattern of lights that harden the liquid into the pattern. The plate incrementally moves deeper into the liquid allowing new liquid to flow over the hardened polymer. Another pattern from the lights hardens the new layer. The process repeats itself by forming a new layer during each repetition.
Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements.